Cogito, Ergo Sum:

René Descartes is the philosophical architect of our modern world. In metaphysics, he established the view that mind and body are distinct substances, which is foundational for any belief that the human soul is immortal. In mathematics, he invented analytic geometry — the basis of calculus—which makes physics as we know it possible. Descartes perfected the method of proposing and testing hypotheses with experiments that anyone could repeat, which forms the basis of modern science. In optics, he discovered and described laws of refraction and reflection. In medicine, he was a pioneer in vivisection and anatomical description for understanding the human body. In physiology, his analysis of the relations among the sense organs, nerves, and the brain is still taught today. In psychology, he discovered conditioned reflexes and investigated the role of the emotions in human behavior.

Descartes said there was no point in trying to refute Aristotelian Scholasticism; rather, he would simply show a better way. Some 350 years after his death, our twenty-first century world—from mind-body dualism to heart pumps, from pop psychology to personal computers—is thoroughly Cartesian. Nothing in the modern world would alarm, or surprise, Descartes were he alive today.

Descartes’s motto was that a life well hidden is well lived. Much of his own life is obscure to us now, which has led to tales of the great philosopher lying in bed meditating each morning until eleven, piously following the dictates of a Cardinal, writing verses for a Queen, and so on. Many of these myths are exploded in Cogito Ergo Sum, the first biography published since 1920 based on extensive original archival and field research. It is also explicitly the life of Descartes, in the flesh and blood, not a compendium of technical analyses of philosophical positions found in “life and works” biographies so dear to contemporary professional philosophers.

For more than forty years Watson has pursued Descartes in libraries and in the locales throughout Europe where Descartes studied, wrote, lived, and finally died. In this sometimes idiosyncratic and iconoclastic book, impeccably researched but amazingly readable, Watson brings Descartes and his milieu to life as has never been done before. Cogito Ergo Sum is certain to be the standard life of Descartes against which all future biographies will be judged.

Praise for Cogito, Ergo Sum

This is unlike any other book on Descartes I know of. . .It is exciting to accompany Watson through the countryside of rural Holland and France, through the twisted streets of old Stockholm, through the dusty books and archives, listening to his crusty comments and sometimes wild conjectures. . .Whatever the results of the scholarly debates that this book occasions, what emerges is a vivid picture both of Descartes and of Watson himself. —Daniel Garber,

For all of his puckish delight in a juicy anecdote, Watson recognizes and carefully explicates the cultural centrality of Descartes’ intellectual legacy. That legacy ensures numerous readers sure to praise a biographer who delivers both the philosopher’s cerebral doctrines and his unmistakably human conduct. —Booklist

he narrative…is both rigorous and engrossing and readers will see clearly how pertinent the seventeenth-century Descartes is to the modern world. —Library Journal